Device for generation of pulses



Jan. 24, 1956 EMANUELSSON 2,732,527

DEVICE FOR GENERATION OF PULSES Filed June '7, 1952 2 Sheets-Sheet 1 Fig. 7

Fig.3

Fig. 4

Mi Ha:

Jan. 24, 1956 EMANUELSSQN 2,732,527

DEVICE FOR GENERATION OF PULSES Filed June 7, 1952 2 Sheets-Sheet 2 firm/war United States Patent DEVICE FOR GENERATION 0F PULSES Gunnar Gideon Emanuelsson, Hagersten, Sweden, as-

signor to Telefonaktiebolaget L M Ericsson, Stockholm, Sweden, a company of Sweden Application June 7, 1352, Serial No. 252,337 Claims priority, application Sweden June 12, 1951 8 Claims. (Cl. 332-9) To obtain a voltage, the wave form of which having sharply defined steps, by the help of a device, consisting of a series connection of a source of voltage, a resistor, a rectifier and an inductance is previously known e. g. by the Swedish Patent No. 80,694. These steps occur with a frequency equal to the frequency of the voltage source. This invention relates to a device for generation of pulses with large amplitude, which device mainly comprises two series connections of the kind previously mentioned. Contrary to usually existing pulse generators no electron tube device is thus required, which fact in certain connections may be advantageous. A device according to the invention may be said to be characterized by its comprising two main circuits, each of them intended for generation of a voltage with sharply defined steps and consisting of a'series connection of a source of voltage which is arranged to deliver a voltage of a relatively high frequency, a resistor, a rectifier or the like and an inductance, said two inductances having one point in common and being connected in series with each other through two series connected resistors, and by which on one hand the total resistance of one of the main circuits differs from the total resistance of the other main circuit by, a certain determined value depending upon the duration of the wanted pulses, on the other hand the voltage sources and the rectifiers of the two main circuits are so arranged as to cause voltages occurring over the inductances to get opposite signs.

a The invention will be closer described in connection with the accompanying drawing, where Fig- 1 shows a circuit diagram of a device according to the invention; Figs. 2 and 3 show diagrams of voltages and pulses, which'diagrarns are intended to facilitate the explanation of the function of the device according to Fig. 1; Figs. 4 and 5 show two modifications of the device according to Fig. 1; and Figs. 6, 7, 8, and 9 finally show corresponding pulse diagrams.

The device according to Fig. 1 may be said to consist of two main circuits, each of them intended for generation of a voltage with sharply defined steps. One of the main circuits comprises a series connection of a winding 11 of a transformer 11, arranged to deliver a voltage of a relatively high frequency, a resistor 12, a rectifier 13 and an inductance 15, which is shunted by two series connected resistors 16 and 20. The other main circuit comprises a series connection of a winding 21 of a transformer 1021, arranged to deliver a voltage of the same frequency as the transformer 10-11, a resistor 22, a rectifier 23 and an inductance 25, which is shunted by two series connected resistors 26 and 20. The windings 11 and 21 form together the secondary winding of a transformer 101121, the primary winding of which being indicated by 10 in Fig. 1. The windings 11 and 21 and the rectifiers 13 and 23 are so arranged as to cause voltages occurring over the inductances and 25 to get opposite signs. The output terminals of the de- 2,732,527 :I atented Jan. 24,

vice are connected to the ends of the common resistor 20 and indicated by 17 respectively 27 in Fig. 1.

The device functions as follows: If a sinusoidal voltage of a certain frequency is applied'to the transformer 10-1121, a voltage will be obtained over each of the two inductances 15 and 25, the wave form of said voltage having sharply defined steps depending upon the non-linear properties of the rectifier and the phase shifting influence of'the'inductance on the current inrela} tion-to the voltage in respective main circuit. In Fig. 2 a curve 14 shows the wave form of the voltage over the inductance 15 and a curve 24 the wave form of the voltage over the inductance 25. As is shown by the curves 14 and 24 a step in the voltage over each of the inductances occurs once per cycle of the sinusoidal voltage of the transformer. The voltage over the inductance 15 has steps at the times and the voltage over the inductance 25 at the times am ne;- where 1 indicates the frequency of the sinusoidal voltage. By dimensioning each of the main circuits in a suitable manner and taking out a sum voltage over the common resistor 20, a pulse may be obtained, the duration of which will beequal to the time difference between the times forthe occurrence of twoadjacent steps, see Fig. 3. Pulses with a duration of about 10 a sec onds will be obtained, if themain circuits are dimensioned in the following manner: Each of the inductances 15 and 25 being 10 millihenries, each of the resistors 16 and 26 being 50 kohms, the resistors 20, 12 and 22 being 300 kohms, l kohrn and 2 kohrns respectively and the frequency of the sinusoidal voltage being 8000 c./sec. In the shown example with the resistance 22 being greater than the resistance 12 positive pulses are obtained. When the resistance 12 is greater than the resistance 22, negative pulses will be obtained.

The device according to Fig. 4 differs from that one previous described by its comprising devices for modulation' of the generated pulses. These devices are-intended-to apply a voltage of a relatively low frequency to one of the main circuits. This is made either via a transformer 27-28 and a condenser 18, or-if said voltage is a direct voltagevia a series circuit, comprising a resistor 29, a relay 30 and a battely 31. The secondary winding 27 of the transformer 27-28 is via the condenser 18 connected to a resistor 37, which is connected between the inductance 15 and the connection point of the resistor 20 and the winding 11. The resistor 29 is connected to the connection point of the inductance 15 and the resistor 37. One terminal of the battery 31 is connected to the connection point of the resistors 37 and 20. The relay 30 will close the series circuit, when a relay winding 32 gets current. In Fig. 6 there is shown a pulse train, which is obtained, when a low frequency modulation voltage is applied via the transformer 27-28. The trailing edges of the pulses occur at determined times 2 5 i. e. independent of the modulation voltage and with an interval between two successive trailing edges of while the duration of the pulses varies in dependence of the modulation voltage. If instead the resistor 37 is connected in the. other main circuit, a train of pulses according to Fig. 7 will be obtained, i. e. the leading edges of the pulses will occur at determined times a; we; 1+;

independent of the modulation voltage, while, as previous, the duration of the pulses will vary in dependence of said modulation voltage. Fig. 8 shows a pulse train, which is obtained, when, a direct voltage is applied. as a modulation voltage by the relay winding 32 being current carrying. The pulses obtained have all a duration 12, which considerably exceeds the duration 22-11 of a non-modulated pulse according to Fig. 3. In signal translating devices comprising both voice frequency currents and ringing currents the device according to Fig. 4 is suitable. because the voice currents may be applied via the transformer 2728 and the ringing currents via the, relay winding 32.

In Fig. there is shown a device, by which pulses may be generated and modulated in such. a manner that the middle lines of the pulses will always occur at certain determined times i. e. not depending upon the modulation voltage. This is made possible by the modulation voltage being applied to a winding 34 of a transformer, the other winding 33 of which being connected, between the connection point of the windings 11 and 21 and the resistor 20. Thus the two main circuits will get a common voltage source. In this case too it is of course pos sible. to realize. modulation in the same manner as is shown by Fig. 4, so that both voice. currents and ringing currents may be transmitted.

It may further be emphasized, that a modulation voltage source. may be connected between the. transformer winding 11 (21) and the resistor 12 (22) or between the resistor 12 (22) and the rectifier 13 ('23), or be.- tween the rectifier 13 (23) and. the inductance 15. (25) or between the inductance 15 (25.) and the winding 11 (21) within the scope of the invention.

I claim:

l. A network for producing short pulses having a high amplitude comprising, two circuit systems for generating two voltages having sharply defined steps, each of said circuit systems including a source of. voltage of comparatively high frequency connected in series with resistance means, rectifying means and. inductance means, the. said two inductance means being connected with one end to a common point and with the other end through two resistance means in series, the total resistance of one of said circuit systems being different from that of the other circuit system by a resistance value corresponding to the desired width of the short pulses delivered by the network, and the said rectifying means being connected in opposition to permit in one circuit system a current flow through one of said inductance means to the common point and in the other circuit system from the common point through the other inductance means thereby generating voltages having opposite signs over said inductance means, the common point of the two inductances and the common point of the two resistance means constituting the output terminals for the pulses.

2. A network according to claim 1, wherein the said rectifying means in each circuit system have a non-linear characteristic.

3. A network according to claim 1, wherein a third resistance means is connected with the common point of said two resistance means and the. common point of said two inductance means, the said third resistance means being common to both circuit systems.

4. A network according to claim 1, wherein the voltage sources of said two circuit systems comprise a transformer means having a split secondary, each circuit system being connected to the. transformer means across the midpoint and the respective end point of said secondary.

5. A network according to claim 1 and further comprising a source of a bias voltage connected with one. of said circuit systems, the said voltage source being adapted and connected to modulate the pulses produced by the network.

6. A network according to claim 5, wherein the said source of a bias voltage delivers an alternating voltage of a comparatively low frequency.

7'. A network according to claim 5, wherein the said source of a bias voltage delivers a direct voltage.

8. A network according to claim 1 and further comprising a source of a bias voltage connected in circuit with both said circuit systems, the said common source of voltage being adapted and connected to modulate the pulses produced by the network.

References Cited in the file of this patent UNITED STATES PATENTS 1,921,787 Suits Aug; 8, 1933 2,168,402 Fitzgerald Aug. 8, 1939 2,304,135 Wise Dec. 8, 1942. 2,443,195 Pensyl June 15, 1948 2,666,901 Lynn Ian. 19, 1954 

